So ... Nothing in syslog but as expected in pveproxy/access.log the same 401...
BUT I going to kick the admin. There are several different proxmox versions in the cluster.
5.1-43, 5.2-8, 5.3-11, 5.3-12, 5.4-3
and if 5.3-11 asked all in the cluster everything works fine
but if a host with 5.1...